Roscoe does not browse. Users can import a file into their Active Work Space (AWS) to work with it. The maximum number of lines that can be imported is a parameter that can be set in Roscoe. However, the largest value for this parameter is 32000. It does not matter how many characters are on the line as long as it is not greater than 255. If the length of the line is greater than 255, you will not get an error, but the line will wrap and each line of the file will use up 2 lines in the AWS, reducing the total line limit to 16000.
You can have multiple AWS's, and bring in sections of a file.
Read more at http://www.ca.com/us/support/ca-support-online/product-content/knowledgebase-articles/tec583702.aspx
Please let me know if you have questions.
Thank you, Nancy CA Support